"Why the left should argue for more immigration – but not open borders
The US needs more immigrants to maintain current levels of economic
growth and welfare provision – but that doesn’t mean unlimited migration."

"A more plausible objection concerns immigration’s distributive effec ...[text shortened]... make sure that the
aggregate benefits of immigration are shared fairly within society as a whole."

The Left is too scared to make such an argument. It is far easier just to call anyone who opposes open borders as a bigot. In fact, they have about half the support of the country making such arguments, so why change now?

The added bonus is, open borders also allows in law breakers, such as MS 13, which further pushes the narrative for the need for a police state and less freedom for US citizens. For example with each successive "shooting" provides more fodder for the argument of confiscating all guns from the populace.